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(No Model.)

F. H. THOMPSON.

INSULATED WIRE EOE ELECTRICAL PURPOSES. No. 274,845. Patented Mar'.27,1883.

UNITED STATES PATENT OEEICE.

FRANK H. THOMPSON, OF WATERBURY, CONNECTICUT, ASSIGNOR TO THE BENEDICT St BURNHABI MANUFACTURING COMPANY, OF SAME PLACE.

INSULATED WIRE FOR ELECTRICAL PURPOSES.

SPECIFICATION forming part of Letters Patent No. 274,845, dated March 27, 1883. Application tiled March 25, 1852. (No model.)

To all whom it may concern Be it known that I, FRANK H. THOMPSON, of Waterbury, in the county of New Haven and State ofConnecticut,have invented a new Improvement in Insulated Wire forElectrical Purposes; and Ido hereby declare the following, when taken in connection with accompanying drawings and the letters of reference marked thereon, to be a full, clear, and exact 1o description of the same,and which said drawings constitute part ot' this specitication, and represent, in-

Figure 1, alongitud'inal central section, showing the different steps in 'the manufacture; and

Fig. 2, a transverse section, both enlarged.

This invention relates to an improvement in theinsulated Wire used for electrical purposes, withspecial reference to thatused i'or electric lights. This class of wire` requires to beinzo sulated. Various devices have been resorted to to make a perfect and durable insulation. White lead has been used because ot'its insulating property and the protection which it gives from the surroundingatmosphere, it being water-proof. This is usually applied in the form of paint-that is, lead mixed with oil; but a serious diiiculty exists in the use of this insulated Wire from the fact that paint soon hardens and is liable to crack and ake7 3o from the covering, and thereby expose the wire to dampness and other external in liuences, as well as to destroy the insulation. Again, in applying the lead and oil, a long time is required for drying the painted surface, such drying occupying considerable space.

Y The object ot' my invention is to use the lead but dispense with the oil, which not only hardens the lead and causes its cracking and laking, but requires a long time to dry and properly harden.

To this end my invention consists iu a wire covered with cotton, by braiding, winding, or otherwise, then coating this covering with pure lead or zinc mixed with benzine and patent drier, as more fully hereinafter described.

I first cover the WireA with cotton, as at b, by braiding or winding in any of the known machines, or it may be otherwise covered. For the coating I mix one gallon benzine, twenty- 5o five pounds lead ground in oil, and three ounces patent drier. This produces the best results; but the proportions may be varied without departing from my invention. The article which I term patent drier77 is well known in commerce by that name, and needs no particular description ot' its composition. These ingredients I thoroughly mix. They form a paste-like compound. Through this mixture I draw the covered wire, passing it through a wiper as it leaves the mixture, to 6o take ol' the surplus. This coating sets very quickly, and then it is wiped again. This second wiping may be done by drawing it through a wiper at some little distance from the tirst wiping operation, leaving the cotton covered as seen at e. No further time is required for the drying ofqthis coating. It is at once sufficiently hard for market or for use. It is very elastic, will permit very short bends in the wire without cracking, does not tlake, and has 7o none of the objections to the mixture of lead and oil heretofore used.

In some cases, as for interior work, a thicker coating is required, because of the dangers which have arisen from `the use of improperlyinsulated wires. In such cases I apply a second covering of cotton over the coated first covering in like manner as I applied the first covering, then draw the wire with this second covering through the mixture again, and treat 8c it as before, forming the outer coating, c, and this may be repeated to any desirable extent, the subsequent coatings having the same elasticity and in no way detraeting from the elasticity of the previous coatings.

It will be understood that the term cotton for covering is intended to embrace any of the materials used for such purposes.

I claim- As an article of manufacture,wire havingits 9o surface covered with cotton, and upon this cotton a coating composed of lead. or zinc ground in oil, benzine, and patent drier, in the proportions and substantially as herein described. h

FRANK H. THOMPSON.

Witnesses:

D. L. HUNGEREOED, GHAs. DIoKrNsoN. 

